This is a blank spot that's glossed over in most of the history sources I read, but how exactly do sort of informal or de facto powerbrokers force more formal, legitimate, or de jure authorities to play ball or cede ground while remaining legitimate? Take, for example, Japan during the Kenmu Restoration and its fallout, where a Japanese Emperor sought to restore the imperial family to actual power and was put down by a shogun-to-be called Ashikaga Takauji. Ashikaga forced the emperor to abdicate, but how exactly? From the limited amount I know about Japanese imperial ideology, it wouldn't be an option to kill or threaten a sitting emperor or the imperial family. Literally nobody would have supported that move. What would Ashikaga have to force him to do that? What did that conversation look like? Why didn't the Emperor just say no, or order him to stop all that treasonous nonsense? If the Emperor had told him to stop, how would Ashikaga maintain the appearance of legitimacy?

I'm not disputing that de facto power loci do usurp de jure or obsolete power loci. It seems like it happens all the time. But with the possible exception of better documented modern examples or the Carolingian mayors of the palace asking the Pope permission to overthrow the Merovingians, I'm curious about how that happens at the moment of pivot without losing the legitimacy that's conferred by the older, maybe obsoleted power source. Ostensibly that legitimacy is why these de jure authorities are kept around in the first place, but it's vague how they lose de facto power in the first place, let alone why they aren't able to actually use their legitimacy to wield real authority? This is becoming sort of a ramble at this point, but when I see history books talk about how Shoguns use nudges to rule for the Emperor, even against his wishes, and Hapsburgs use winks to render a de jure elective institution de facto hereditary, I have to think there's more that goes into it than that, and I'm curious about that mechanism.